The scariest movie news I’ve heard in recent years is that Lee Eisenberg and Gene Stupnitsky were said to be writing the script for "Ghostbusters 3."

These gentlemen have written fifteen episodes of The Office, and some of the better ones, too; but they have also written two of the most aridly, arrogantly unfunny “comedies” ever to see the light of a projector — 2009’s ghastly Year One, and now Bad Teacher. I fear for Ghostbusters 3 (granted, a terrible idea to begin with). The men who wrote the instant-classic Office episode “Scott’s Tots,” perhaps the most exquisitely uncomfortable comedy segment in television history, are obviously not bums. But something seems to happen to their brains when they write a movie.

The one joke here is that Cameron Diaz, as the eponymous bad teacher, is foul-mouthed and shallow and couldn’t care less about building young minds. In a way, it’s a relief that the script doesn’t go the usual route of Diaz having a change of heart and becoming a good teacher. But the movie offers nothing to replace the clichés. Diaz’ character, who’s in it only to get enough money for breast implants, spends half the movie trying to seduce substitute teacher Justin Timberlake, who she assumes has family money, and trying to ruin perky teacher Lucy Punch, whose crime appears to be competence in her job and the insight to know that Diaz is breaking moral, ethical and legal rules right and left.

For this, Punch’s character is punished from beginning to end, first by being named Amy Squirrel, then by being cheated on, rubbing a poison-ivy-coated apple over her face, being arrested for possessing drugs that are actually Diaz’, and finally getting transferred to another school district to teach at an urban rathole named after Malcolm X. That last bit is supposed to be funny, I guess: the perky little white teacher is being banished to what we presume is a predominantly black school, where terrible things are sure to happen to her. Because, you know, the kids are black. Does anyone involved with this movie even know any black people? If so, were said people shown the script, and if so, did that joke fly at all?

Sure, Diaz’ character doesn’t undergo some clichéd redemption, but she doesn’t evolve in any other way, either. She pretty much stays shallow. Which would be fine if it were funny. As it is, the closest she has to an awakening is when gym teacher Jason Segal, who has his eye on her, points out that Timberlake is an airhead who will say anything he thinks his conversation partner will agree with. It’s a weird time for the movie to come out in favor of intellectual integrity. As for Segal, his scenes with Diaz feel as though they were tacked on in reshoots. He doesn’t really interact with anyone else (the “That’s all the argument I need, Sean!” bit you’ve seen endlessly in the commercials could be lifted whole out of the film with no harm done, and all his other scenes with it), and he exists only to give Diaz a kinda-sorta happy ending.

Which she doesn’t deserve. She deserves, as Punch’s character rightly says, jail time. She has helped her class cheat on an important test (by stealing the answers) so she can get a $5,000 check to put towards her implants. She drinks and gets high on school property. Again, this could all work if it were funny. Diaz, who slouches sullenly through the movie as if fulfilling a contractual obligation (or saving up for implants), is pitted against Lucy Punch, an unfair contest: Despite working with the same dreary script, Punch puts her whole physicality into the performance and ends up being infinitely more likable by comedic default. She’ll be in better movies, I hope.

As for Diaz, she should take a long hard look at "Bridesmaids" — or even her own "The Sweetest Thing," from nine years ago — and see how a female-centered comedy is supposed to work. Being funny, for starters.